Menu
Search
Filters
Close
Menu

02194 MODELLING THE EFFECTS OF CREVICE GEOMETRY AND OXYGEN ON CREVICE CORROSION OF PURE CHROMIUM AT CONSTANT PH AND VARIOUS CHLORIDE CONTENTS

Picture for 02194 MODELLING THE EFFECTS OF CREVICE...
Available for download
Product Number: 51300-02194-SG
ISBN: 02194 2002 CP
Author: Hans Hoffmeister
$0.00
$20.00
$20.00
In a recent paper a crevice corrosion model for pure chromium was presented aiming at basic understanding of the local corrosion mechanism in an already deoxygenated crevice with a given geometry. The time stepwise calculation of chromium dissolution was based on arbitrarily selected levels of initial corrosion potential and slopes of the cathodic polarization curve at the open surface in contact with the bulk liquid. As a basic feature, the anodic polarization slopes inside the crevice were controlled by the mass of precipitated chromium hydroxide which was thermodynamically calculated from the resulting crevice solution composition using the tentative ternary phase diagram water -chromium- chromium hydroxide - chromium chloride. The present paper applies additional oxygen diffusion calculation steps and demonstrates the effects of various crevice widths and bulk oxygen contents diffusing into the crevices at pH = 6 and chloride contents of 7 and 13 %. The calculations are based on the assumption of chemical equilibrium conditions as well as on rather short electromigration times of the chromium controlled chloride ions complementary to the OH ions resulting from oxygen diffusion and reduction during the individual time steps. It is shown that increasing bulk oxygen levels and crevice widths are retarding the breakdown times of the passivating chromium hydroxide, while, under the given conditions, increasing chloride contents mainly reduce the crevice corrosion incubation times. As a specific result it is also demonstrated that after chromium hydroxide break down, the times for consecutive repassivation by restart of the chromium hydroxide precipitation inside an active crevice are reduced at increasing bulk oxygen levels. Keywords: Crevice corrosion modelling, chromium, crevice geometry, oxygen, chromium hydroxide.
In a recent paper a crevice corrosion model for pure chromium was presented aiming at basic understanding of the local corrosion mechanism in an already deoxygenated crevice with a given geometry. The time stepwise calculation of chromium dissolution was based on arbitrarily selected levels of initial corrosion potential and slopes of the cathodic polarization curve at the open surface in contact with the bulk liquid. As a basic feature, the anodic polarization slopes inside the crevice were controlled by the mass of precipitated chromium hydroxide which was thermodynamically calculated from the resulting crevice solution composition using the tentative ternary phase diagram water -chromium- chromium hydroxide - chromium chloride. The present paper applies additional oxygen diffusion calculation steps and demonstrates the effects of various crevice widths and bulk oxygen contents diffusing into the crevices at pH = 6 and chloride contents of 7 and 13 %. The calculations are based on the assumption of chemical equilibrium conditions as well as on rather short electromigration times of the chromium controlled chloride ions complementary to the OH ions resulting from oxygen diffusion and reduction during the individual time steps. It is shown that increasing bulk oxygen levels and crevice widths are retarding the breakdown times of the passivating chromium hydroxide, while, under the given conditions, increasing chloride contents mainly reduce the crevice corrosion incubation times. As a specific result it is also demonstrated that after chromium hydroxide break down, the times for consecutive repassivation by restart of the chromium hydroxide precipitation inside an active crevice are reduced at increasing bulk oxygen levels. Keywords: Crevice corrosion modelling, chromium, crevice geometry, oxygen, chromium hydroxide.
PRICE BREAKS - The more you buy, the more you save
Quantity
1+
5+
Price
$20.00
$20.00
Product tags
Also Purchased
Picture for 02213 THE INFLUENCE OF ENVIRONMENTAL FACTORS...
Available for download

02213 THE INFLUENCE OF ENVIRONMENTAL FACTORS ON THE CREVICE CORROSION OF ALLOY 625 IN NATURAL SEAWATER

Product Number: 51300-02213-SG
ISBN: 02213 2002 CP
Author: F. J. Martin, P. M. Natishan, K. E. Lucas, E. A. Hogan, A. M. Grolleau, and E. D. Thomas
$20.00
Picture for Effect of Temperature to Crevice Corrosion of Austenitic and Duplex Stainless Steel in Deepwater
Available for download

51312-01361-Effect of Temperature to Crevice Corrosion of Austenitic and Duplex Stainless Steel in Deepwater

Product Number: 51312-01361-SG
ISBN: 01361 2012 CP
Author: Jing Wang
Publication Date: 2012
$20.00
Picture for 97417 A SIMPLE MODEL OF CREVICE CORROSION
Available for download

97417 A SIMPLE MODEL OF CREVICE CORROSION PROPAGATION FOR STAINLESS STEELS IN SEAWATER

Product Number: 51300-97417-SG
ISBN: 97417 1997 CP
Author: Per Olav Gartland
$20.00
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support